In any location or facility where a hydrocarbon liquid such as crude oil is produced from a subterranean reservoir, an amount of water as well as gas will be included in the production flow. As an economic expedient it is desirable to separate these fluids into discrete streams that can be more readily handled downstream.
In the instance of the gaseous components to the produced stream, if the gas is present in a sufficiently large quantity it will be separated from the liquid and accumulated for further use or storage. Where, however, the gas is in a minimal or token quantity, it will be flared off.
In the instance of the water/oil mixture, gravitational separation of the two can be achieved economically. This, however, is done at a relatively slow pace. Functionally, when the combined water/oil mixture is introduced into a common separating, or wash tank, the lighter component will rise to the surface and can be separated from the water. Ideally, this operation is accomplished by maintaining the combined liquids in a relatively quiescent condition; stated otherwise, to minimize or eliminate turbulence in the separating part of the tank.
Toward achieving this ideal separating condition, the water/oil mixture must be introduced to the separating tank in a manner to avoid turbulence at the bottom of the tank. Turbulence is ordinarily caused by a rapidly incoming flow of the mixture from a well. To minimize turbulence, the separating tank is usually provided with a distribution or spreader plate which extends transversely of the tank near its bottom or lower side. The spreader plate functions in one respect to divide the tank into upper and lower segments.
Toward improving the functioning of the perforated spreader plate, and in accordance with the present invention, an incoming oil/water mixture is directed toward the bottom surface of the spreader plate from a plurality of judiciously arranged risers. This arrangement avoids the forceful discharge of incoming produced fluid streams against a limited area of the spreader plate underside, which precludes establishment of a turbulent condition.